The present invention relates to semiconductor structures, and more specifically, to integrating Vertical FETs with FinFETs.
FETs are commonly employed in electronic circuit applications. FETs may include a source region and a drain region spaced apart by a semiconductor channel region. In planar FETs, the semiconductor channel region may be a semiconductor substrate. In finFETs, the semiconductor channel region may be a semiconductor fin. A gate, potentially including a gate dielectric layer, a work function metal layer, and a metal electrode, may be formed above the channel region. By applying voltage to the gate, the conductivity of the channel region may increase and allow current to flow from the source region to the drain region.
Fin field effect transistors (FinFETs) are an emerging technology which may provide solutions to field effect transistor (FET) scaling problems at, and below, the 22 nm node. FinFET structures may include at least a narrow semiconductor fin gated on at least two sides of each of the semiconductor fin, as well as a source region and a drain region adjacent to the fin on opposite sides of the gate. FinFET structures having n-type source and drain regions may be referred to as nFinFETs, and FinFET structures having p-type source and drain regions may be referred to as pFinFETs.
Vertical field effect transistors (VFET) are an emerging technology that may allow scaling below 15 nm due to their unique geometry. As compared to FinFETs, which are oriented such that current flows parallel to the surface of a die, with source/drain contacts oriented in similar direction, VFETs are aligned such that the current flow normal to the surface of the die, and having a gate layer parallel to the surface of the die, and surrounding the channel of the VFET. This may decrease the footprint of the structure on the surface of the die, as well as improving leakage across the gate, due to the gate surrounding the channel.
By integrating FinFET and VFET type transistors, more efficient devices may be created.